Mussels near a submarine volcano survived for several decades despite the presence of extremely acidic waters, reports a study published online this week in Nature Geoscience. The findings provide a glimpse into an ecosystem's response to ocean acidification, as is expected from the rising levels of atmospheric carbon dioxide.

Verena Tunnicliffe and colleagues studied mussels on Eifuku volcano, part of the Mariana arc in the Pacific Ocean. Liquid carbon dioxide emerges in this hydrothermal setting and renders the water in the vicinity of the volcano significantly more acidic than average ocean water. For comparison, they authors looked at mussels of the same species in more amenable waters. The shell thicknesses and growth rates of the mussels in acidic waters were only about half that of shells in more typical ocean conditions.

Crabs ― mussels' natural predators ― were absent in the highly acidic setting, probably because of the inhospitable conditions. The lack of predators could have facilitated the mussels' survival over up to the past four decades despite their thin shells.